The present invention relates to surface protective coatings and more specifically to peel-off (peelable) coatings effective for protecting exposed surfaces of various products and components. In particular, the coatings are suitable for protection of vehicles and vehicle components.
The surface paint finishes of new vehicles are subject to a variety of injuries both during the assembly process and during transportation from the assembly plant to retail locations. These finishes are especially prone to damage in the first month following manufacture because the paint has not had sufficient time to cure. Typical sources of damage include acid rain, bird droppings and "rail dust", a cloud of hard, abrasive particles which rises from a rail bed as a train passes over the rails. Rail dust is an especially difficult problem for car manufacturers as many cars are transported form assembly plants or dockyards to retail markets by rail. The damage inflicted on the vehicles' surface finish during transit can be quite severe, even requiring shipment back to the assembly plant for complete repainting.
In addition to new vehicles, other products are also subjected to abrasive and deleterious conditions during transit, and during fabrication and assembly into other products. For instance, storm windows and other glass products must be specially protected to avoid scratching and marring during road and rail transit. Deck cargo is also susceptible to surface damage caused by salt water and other factors. Similarly, many products must be protected during fabrication or assembly by downstream manufacturers. For example, plastic laminates such as Formica.RTM. and other materials with high-gloss finishes such as bathroom fixtures and chrome plated or brass surfaces must be protected not only during shipping, but during installation or assembly into other products.
Various approaches have been utilized to protect the exposed surfaces of vehicles, vehicle components, and other products during manufacture and transportation. The simplest approach, physical protection with solid coatings (e.g., covering the vehicle or component with plastic or canvas) is effective, but it is labor intensive and therefore prohibitively expensive for mass shipments. Plastic sheeting, for example, is as much as ten times more expensive to use than chemical coating solutions due to higher material costs and the amount of labor needed to properly apply the sheetings. In addition it is difficult, time consuming and sometimes virtually impossible to apply solid sheet coatings to complex or convoluted surfaces.
Solution-type protective compositions are known, but have not found widespread use because of the damage which may possibly occur to the underlying or adjacent surfaces. These compositions are often difficult to remove from certain surfaces (e.g. underlying plastics). Also, traditional chemical methods suffer from high cost and the health and environmental dangers posed by solvent-based solutions and coatings.
Aqueous emulsion type coatings are also easily applied and eliminate the problems associated with various organic solvent systems. The most widely used are polyvinyl acetate emulsions or acrylic resin emulsions. These emulsions, however, are defective with respect to heat stability, resistance to water and stability in storage, and low drying velocity after application. For example, those disclosed in Japanese Patent Publication No. 14770/73 which are prepared by adding floury materials such as calcium carbonate and titanium dioxide, silicone resin and an aqueous emulsion of paraffin wax are defective in their poor stability when stored for a long time, and also in their low drying velocity after application. In addition many coatings tend to cross-link, particularly after exposure to sunlight (UV radiation) or elevated temperature, and become very difficult to remove.